1. Field of the Invention
The present invention relates to a steering lock device locking rotation of a steering shaft of a vehicle.
2. Description of the Related Art
This type of a conventional steering lock mechanism is disclosed in Japanese Patent Laid-open Publication No. 2007-55546. As shown in FIGS. 1 and 2, the conventional steering lock mechanism 100 includes a key lock collar 103, a lock member 104, a steering lock body 105, and a supporting bracket 106. The key lock collar 103 is attached and fixed to a steering shaft 102 provided within a steering column. The lock member 104 is a rotation limiting member which is movable in a radial direction of the steering shaft 102 and fittable to the key lock collar 103. The steering lock body 105 abuts on an outer circumferential surface of the steering column 101. The supporting bracket 106 is attached to the steering lock body 105 and supports the steering column 101. One end of the supporting bracket 106 is fastened to the steering lock body 105 by a bolt 107 and the other end of the supporting bracket 106 is attached to the steering lock body 105 through an attachment section 108. The attachment section 108 includes: a pair of bearing portions 110 formed in the steering lock body 105; a supporting shaft 109 inserted through the pair of the bearing portions 110; a shaft supporting portion 111 formed by bending the other end of the supporting bracket 106 and axially supported by the supporting shaft 109; a shaft support cancellation preventing portion 112 extending from the shaft supporting portion 111 towards the inner circumferential surface of the supporting bracket 106. The supporting shaft 109, the pair of the bearing portions 110, and the shaft supporting portion 111 constitute a hinge structure. Furthermore, a distance between the pair of the bearing portions 110 in an axial direction is set a little larger than a width of the shaft supporting portion 111. A width of the shaft support cancellation preventing portion 112 is set larger than the distance of the pair of the bearing portions 110.
In the conventional steering lock mechanism 100, the steering shaft 102 is coupled to a not-shown steering wheel. The steering shaft 102 is rotatably supported by the steering column 101. When a driver of a vehicle turns the steering wheel, turning force is transmitted through the steering shaft 102 to a not-shown steering device. Moreover, when a not-shown ignition key is taken out, the lock member 104 moves towards the steering shaft 102 and is fitted to the key lock collar 103. This restricts the rotation of the steering shaft 102, thus rendering the vehicle unsteerable. If the steering wheel is forced to rotate in a state where the steering shaft 102 is in a locked status described as above, the steering shaft 102 is subjected to large rotary torque. The supporting bracket 106 is accordingly energized outward. The shaft supporting portion 111 is therefore pulled and is exposed to stress so as to cancel the shaft support. At this time, an end of the shaft support cancellation preventing portion 112 in the width direction comes into contact with upper surfaces of the bearing portions 110 to prevent significant deformation of the shaft supporting portion 111. Accordingly, the supporting bracket 106 is kept attached, and the steering shaft 102 is kept the locked status. It is therefore possible to prevent a parked vehicle from being stolen.